SK hynix will keep squeezing more out of the 6F² DRAM cell, the architecture the whole industry uses today, with more EUV lithography and process improvements, while Chinese manufacturer CXMT tries to get ahead with the smaller 4F² cell. That’s according to KoreaBizWire and DIGITIMES, which note that the South Korean manufacturer is keeping 4F² and 3D DRAM on its roadmap, but isn’t in a hurry to abandon a technology it already dominates.
SK hynix’s bet on 6F² DRAM with EUV in 30 seconds
- SK hynix will extend the life of the 6F² cell with EUV lithography and process improvements.
- The 4F² cell and 3D DRAM remain on its roadmap, though the sources give no date for their arrival.
- CXMT says it has achieved key breakthroughs in 4F² and promises DDR5 server modules before the end of 2026.
- Samsung is targeting 2028 for mass production of 4F² DRAM, and Micron has ruled out this architecture.
The cell is the basic unit of a DRAM chip: a transistor and a capacitor that store one bit. Its size is measured in multiples of F, the process’s minimum feature size. The 6F² cell, the standard for more than a decade, takes up six units of area; the 4F² cell takes up four, which in theory allows roughly 30% more bits in the same space. The problem is that it requires vertical transistors and a deep change in manufacturing.
SK hynix’s conservative bet
According to DIGITIMES, SK hynix plans to extend the life of its 6F² architecture by leaning on extreme ultraviolet (EUV) lithography and process improvements, and keeps 4F² and 3D DRAM as its next steps. KoreaBizWire frames it as a bet on proven technology over the next-generation designs China is pushing. The available sources don’t detail the number of EUV layers or the timeline for each node.
The decision has an industrial logic: SK hynix is today one of the largest makers of DRAM and HBM memory for AI accelerators, and switching cell architecture carries manufacturing-yield risks at a time of strong demand. EUV lets it keep shrinking dimensions without redesigning the cell, something Chinese manufacturers can’t do, since they can’t buy ASML’s EUV equipment because of export restrictions.
CXMT looks for a shortcut through 4F²
The contrast comes from CXMT (ChangXin Memory Technologies). Its top executive, Cao Kanyu, said on October 10 at an industry conference in Shanghai that the company has achieved key breakthroughs on a 4F² cell with its own vertical gate-all-around transistor, which reduces current leakage. According to Seoul Economic Daily, CXMT plans to launch DDR5 RDIMM modules for servers with this technology before the end of 2026, though it hasn’t published specifications, process details or yields. The approach appears to rely on DUV lithography equipment, the alternative to EUV that it can actually use.
The announcement came at a strong moment for CXMT, which expects to earn nearly $20 billion over nine months thanks to the memory shortage. Samsung and SK hynix shares fell sharply in the following session, though the figures vary depending on the source and the time of day. A Morningstar analyst warned that there can be a considerable gap between unveiling a 4F² product and manufacturing it with profitable yields.
The rest of the industry is split. Samsung is working on sub-10nm 4F² DRAM and is targeting mass production in 2028. Micron, on the other hand, has ruled out bringing 4F² into production and went as far as calling its density advantage a myth. And YMTC, the Chinese NAND manufacturer, is preparing its first DRAM with a 4F² cell. SK hynix’s strategy puts it somewhere in the middle: it isn’t giving up on 4F², but it’s not in a rush to adopt it either.
Frequently asked questions
What’s the difference between a 6F² and a 4F² DRAM cell?
The 6F² cell takes up six units of area per bit and is today’s standard; the 4F² cell takes up four, allowing close to 30% more density, but requires vertical transistors.
What is SK hynix going to do?
According to DIGITIMES, extend the 6F² cell with EUV lithography and process improvements, while keeping 4F² and 3D DRAM on its roadmap.
When will CXMT launch its 4F² DRAM?
CXMT plans to launch DDR5 server modules with this technology before the end of 2026, with no specifications published yet.
What are Samsung and Micron doing?
Samsung is targeting mass production of 4F² DRAM in 2028; Micron has ruled out bringing this architecture into production.
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